#1: Once you're champion, it seems like the most efficient way t' rake in the Pokedollars is to battle at Restaurant Le Wow (located on Autumnal Avenue, accessed via the East-most road on North Boulevard), along with an Amulet Coin and Prize Monies lv. 3. Double battles are the quickest and most efficient. Unless you also want to grind for Experience, this is the way to do it. It costs a not-so-cheap 100,000 just t' dine, but you'll make that back in the first two battles, and after the fifth and final you'll of made a guaranteed 92,000~ profit. Accurately end each battle in the exact specified number of turns, and you'll net 25 Balm Mushrooms which sell for 156,000. Oh, and don't worry 'bout your O-power running out. Restaurant battles are one long segment, and even if an O-power runs out by the time you enter the last battle, they still take effect. T'is why this method is so efficient. Also make sure you have a really powerful team that can one-hit KO lv. 65 opponents.